The present invention concerns a laying-down system for building together with a plant for the primal cutting-up of meat items, namely half carcasses of pigs. The invention also concerns a fully-automatic system for the primal cutting-up of meat items, namely half carcasses of pigs, and comprising a laying-down module, a vision-based detection system for the determination of relevant fix points on meat items, a calculation unit with interface for the controlling of a positioning module and a sawing module. Moreover, the invention concerns a method based on a vision system for primal cutting-up of meat items.
The dividing-up of half pig carcasses is traditionally carried out by an operator placed at a conveyor belt on which the carcasses pass, in that he manually corrects (pulls/pushes) the half carcass in position for a saw (circular knife) which is disposed above the conveyor belt. With this method, use is made of an operator and a saw for each cut which is made in the half carcasses.
The way in which the correction of the half carcasses is typically carried out is that a line laser marker mounted on the individual saws irradiates the conveyor band immediately in front of the saw in an imaginary line through the blade of the saw, and the operator uses this laser beam in moving the half carcass manually so that this is sawn through in the desired place.
The above-mentioned method has several disadvantages. In the first place, the operator""s work is monotonous and physically demanding, and operators who carry out this work are worn-out by the work after a relatively short period. Secondly, the positioning of the cut is based on the subjective judgement of the individual operator, so that the accuracy can fall with changing operators, inattention on the part of the operator, or if he has difficulty in maintaining the necessary concentration over longer periods of time. Thirdly, the definition of the correct knife positioning can change during the course of the production, which necessitates verbal communication of the changed requirements out to a number of operators, which involves possibilities of error.
Efforts have been made to automate the above-mentioned method, for example in DK B 161 656 there is disclosed a semi-automatic plant of the kind whereby an operator moves a position-provider coupled to a laser beam to the positions on the half carcass where he judges that the cuts shall be placed. When the laser beam irradiates the place of the cut, the operator activates an operating element, whereby the position of the position-provider is read into a control system. The positions of the cutting places are used to position the half carcasses and the subsequent saws, so that the different cuts are effected in accordance with the judgement of the operator. The publication also discloses a method for arranging the individual half carcasses so that their lengthways axes are positioned at right-angles to the feeding direction. With the said system, it is thus possible for human errors of judgement to be made in connection with the positioning which determines the cuts which are to be carried out in the half carcasses.
In DK T3 0 594 528, a system is disclosed by which, with the help of mechanical measuring of the half carcasses, it can carry out a tripartition of these (ham and fore-end cuts). The arranging of the half carcasses to the correct angle takes place in connection with the measuring of fix points in the pig carcass, in that this is drawn over the surface of the conveyor by means of the mechanical measuring means.
The above-mentioned methods are based either on manual or mechanical localisation of the fix points which form the starting point for the cutting-up positions.
DK B1 167 462 discloses a vision system for the determination of said fix points on the half of an animal carcass, said vision system being coupled to a computer for the implementation of picture analysis which, after the determination of the position of fix points in a manner which is not specified, is said to send control signals to mechanisms which are not further described, and which on the basis of the positioning of the fix points carry out the arranging of the carcass and of the system""s tools for the cutting-up of said carcass.
However, several different patents and patent applications are to be found which deal with actual vision analyses of meat products, partly with the view of classifying meat products, e.g. for determining the market value, and partly to be able to determine the position of certain structures. Among these there are two German publications, DE C2 41 31 556 and DE A1 41 09 345, to which reference is made when, in connection with the present invention application, vision analysis/determination of fix points on half carcasses is discussed. The precondition for the present invention is thus that the position of the fix points on half carcasses, which are used as starting point for the determination of the individual cuts, takes place by means of said vision system. The vision system comprises a video camera which takes a picture of the half carcass while this passes under the camera on a conveyor. The camera is coupled to a computer, which with specially-developed software recognises the contours and inner structure of the half carcass, such as e.g. vertebrae in the spine and the pubis. Hereafter, with great accuracy the computer calculates the positions of the individual fix points in relation to a given zero line. By means of the computer together with suitable interface and actuators, the positioning of the fix points in relation to the zero line can subsequently be used for effecting mutual positioning of the half carcasses/saws with starting point in a beforehand desired positioning of the cuts in relation to said positioning of said fix points. The positioning can take place either by effecting a displacement of the saws (saw blades) in the lateral direction, still with the blades arranged parallel with the transport direction, and/or by using conveyor plant which can be displaced in the transverse direction by means of actuators.
The above-mentioned method and system is particularly suitable for use when an ordinary xe2x80x9cindustrial cutxe2x80x9d is to be made (double cut where the fore-end and hams are separated from the central piece) at right-angles to the length-ways direction of the carcass, where the half carcasses are transported with the lengthways direction arranged at right-angles to the direction of transport, and where the parting cuts are placed in relation to the positions of the fix points by positioning of the half carcasses on sideways-displaceable conveyors, and positioning of the saws in the sideways direction.
If only a ham cut is to be carried out, which is sometimes known as a xe2x80x9cBelgian cutxe2x80x9d, also in the following, it will not be possible to use the above-mentioned method for automatic parting of the carcass, in that a Belgian cut is effected as an inclined cut in relation to the lengthways direction of the carcass, though still in relation to the positioning of the relevant fix point on the half carcass. When carrying out the parting with this type of cut, it has thus hitherto been necessary to effect the cutting manually with manually-operated saws with laser marking of the positioning of the cut, in that the cut which is carried out here shall extend at an angle in relation to the direction of transport. Neither is the above-mentioned method particularly suitable when it is preferred to carry out an optimised industrial cut, which often involves the placing of the cuts at an angle which deviates from right-angles to the lengthways direction of the carcass.
For solving the above-mentioned problems in connection with the placing of the meat items, there is thus disclosed a laying-down module of the kind which is disclosed and characterised in claim 1.
With the U-shaped laying-down fixtures, it is hereby achieved that the meat item/half carcass, after receipt by being successively fed forwards by the suspension conveyor, is placed in the low points of the fixtures, so that before the laying-down on the laying-down conveyor, these are arranged so that the half carcass in the under-supporting points defined by the low points of the two outermost fixtures is lying in a line which is arranged substantially at right-angles to the transport direction of the laying-down conveyor. There is hereby achieved a very uniform positioning and orientation of the transported carcasses, which by the vertical downwards-directed displacement of the fixtures subsequently places the half carcasses in this position on the laying-down conveyor for transport in the further cutting-up process. Moreover, it will not always be certain that the low point in the centremost fixture lies on the line which can be drawn between the two outermost fixtures.
Moreover, with this construction of the laying-down module, it will be possible to place the two outermost fixtures in a manner in which they are displaced from each other, so that the line between the low points of these fixtures deviates from right-angles to the transport direction of the laying-down conveyor. With this embodiment, the changing of this angle can take place only by constructional intervention, which hardly satisfies the demands concerning flexibility which are placed in connection with the primal cutting-up of meat items, namely in the carrying out of optimised industrial primal cutting up.
The subsequent sub-claims 2-7 disclose how said demands for flexibility can be increased.
Claim 2 thus discloses adjustment means for fine adjustment of the fixtures by relative horizontal displacement along with the spacing between the belt of the laying-down conveyor. In practice, this possibility of fine adjustment will be sufficient in connection with the carrying out of optimised industrial cuts, where most often there is a need only to achieve smaller relative displacements between the low points of the two outermost fixtures in order for the line between these to form an angle which deviates from right-angles to the transport direction of the laying-down conveyor.
On the other hand, if a subsequent ham cut (xe2x80x9cBelgian cutxe2x80x9d) is to be made, it will be necessary to place the fixtures, possibly with the adjustment means disclosed in claim 2, on the angling-out mechanism disclosed in claim 3, whereby the laying-down fixtures are relatively displaced by an actual movement each time a meat item is received from the suspension conveyor, so that the low points of the two outermost fixtures are lying on a line which forms a predetermined angle in relation to the transport direction, so that the carcasses in this position are placed on the laying-down conveyor at an inclined angle, and in this position are transported further by the laying-down conveyor to subsequent steps in the process.
Furthermore, as disclosed in claim 4, the adjustment means can be provided with actuators, so that during operation of the laying-down module, adjustments of the angling-out of the meat items can be carried out before these are laid down on the laying-down conveyor for further transport to subsequent steps in the process.
It will be obvious that the laying-down module will be able to be arranged for receiving half carcasses for primal cutting-up which are transported successively in pairs on the suspension conveyor. A laying-down module arranged for this purpose is disclosed in claim 5, where the related carcasses are angled-out in a laterally reversed manner, but with the same degree of angling-out.
With the view to achieving a further optimisation of the subsequent primal parting process, it can also be advantageous to be able to carry out an adjustment of the angling-out in relation to a fix-point determination such as disclosed in claim 6.
With the view to achieving a well-defined and uniform positioning of the lengthways axes of the half carcasses when these are received, the U-shaped hoop fixtures can be configured as disclosed in claim 7. It is hereby achieved that the half carcasses which are thrown off from the conveyor slide down in the correct position for angle positioning.
A system for the primal parting of meat items, i.e. half carcasses of pigs, and comprising a laying-down module, a vision detection system for the determination of relevant fix points on meat items, a calculation unit with interface for the controlling of a positioning module, and a saw module, is disclosed in claim 8, and can be provided with a laying-down module disclosed in any of the claims 1-7, and which also has the characteristics disclosed in points b and c in claim 8.
The advantages of the system according to claim 8 should be obvious, i.e. providing this includes a laying-down module with all of the characteristics disclosed in claims 1-7, in that there is hereby achieved a fully-automatic system for primal parting of meat items, which practically speaking enables automatically-implemented parting of meat items in accordance with any desired cut positioning, and which also allows continuous optimisation of the cut positioning, not only in relation to average considerations concerning the determination of fix points on a series of transported meat items/carcasses, but optimisation in relation to fix-point determinations carried out on each individual meat item, and subsequent placing of the ideal cut line on the basis of empirical ideal cut lines for a meat item with size and fix-point placing determined by the vision detection system.
A more simple system for primal parting of the disclosed kind can, however, be arranged as disclosed in claim 9.
In claim 10 there is disclosed a method based on a vision detection system for primal parting of meat items, i.e. half carcasses of pigs. The method according to the invention is based on the use of the above-mentioned known vision system for detection of the fix points which form the basis for the positioning of the parting cuts, no matter whether these are standard industrial cuts or ham cuts (xe2x80x9cBelgian cutsxe2x80x9d), or other special cuts such as optimised industrial cuts used in the primal cutting-up, so that manual handling in the cutting-up process is avoided, and also so that human errors in connection with the placing of the cuts are eliminated. In this connection it should be mentioned that the angles V1 and V2 can assume the value zero (typically with industrial parting cuts).
With the invention, use is thus made of the fact that the calculation of the positioning of the fix point in relation to the zero line can be carried out no matter whether the half carcasses arrive at the picture-taking section with the lengthways direction arranged at right-angles to the transport direction, or at an angle which deviates from right-angles.
Whether the half carcasses arrive at the picture-taking section with lengthways direction at right-angles to the direction of transport, or at an angle which deviates from this, is thus determined on the basis of how the primal cutting-up of the half carcasses is to be carried out by the saw module, the blades of which are oriented parallel with the transport direction. If, for example, a traditional industrial cut is to be effected, where the half carcass is divided with a fore-end cut and/or a rear-end cut, it is normally preferred that the half carcass is conveyed into the cutting plant (and herewith to the picture-taking section) with the lengthways direction arranged at right-angles to the transport direction, after which said cut is effected in relation to the pubis and especially the armpit, typically so that upon passage of the positioning module, the half carcass is positioned in relation to the cutting line of the ham saw, with starting point in the positioning of the pubis, and the cut line of the saw system""s fore-end saw is lined up in relation to the position of the armpit.
If a xe2x80x9cBelgian cutxe2x80x9d (ham cut) is to be effected, it is preferred that the half carcass be conveyed into the cutting plant (and herewith to the picture-taking section) with lengthways direction oriented at an inclined angle in relation to the transport direction, after which the cut is effected solely in relation to the position of the pubis, which is made possible by the laying-down module according to the invention.
With the combination between the use of a vision-controlled positioning and cutting-up system and the laying-down module according to the invention, with the invention there is achieved a fully-automatic and very precise cutting-up of half carcasses which shall be parted with Belgian cuts (ham cuts) and optimised industrial cuts, in that the half carcasses are laid down on the laying-down conveyor with the lengthways direction of the carcass at a pre-selected angle in relation to the transport direction, corresponding to the preferred angle with which the cutting-up with Belgian cuts, or optimised industrial cuts, is carried out with a cutting system which has saw blades arranged parallel with the transport direction.